Grays Harbor North Jetty Performance Evaluation and Submerged Spur Feasibility

The Coastal Communities of Southwest Washington supported an investigation of a submerged spur at Gray’s Harbor, North Jetty.  The spur concept was considered an innovative, but relatively unstudied and unproven, type of coastal engineering structure.  A submerged spur was considered for construction on the north side of the north jetty at Grays Harbor in order to reduce costs associated with Operations & Maintenance (O&M) of the Corps’ existing navigation project (dredging and structural rehabilitation) and to reduce the shoreline erosion being experienced at Ocean Shores.

A spur is expected to reduce the amount of sand that reaches the inlet from the north by impounding sand in its lee, thereby reducing dredging requirements. Impoundment of sand is also expected to provide stability to the existing north jetty by reducing wave energy reaching portions of the north jetty and the adjacent beach, sand accumulation would also likely provide more substantial support to the toe of the jetty.

Coastal Communities provided funding in support of an independent study of spur stability to help answer important basic questions concerning rock stability.  The study included development of design waves, analysis of existing published data on stone stability for submerged structures and physical modeling in a large-scale 2D wave flume. 

The physical model study was conducted in the 97 meter long wave research flume at the Canadian Hydraulics Center in Ottawa, Canada to test a rock armor structure and a geobag structure.  Both structures performed satisfactorily in the flume tests.

A comprehensive technical study of the north jetty and a range of alternatives for sediment control including a submerged spur was performed by the US Army Corps of Engineers Engineer Research and Development Center, Coastal Hydraulics Laboratory and Pacific International Engineering, PLLC

Results of the study were published in:

N.C. Kraus, and H.T. Arden, (eds.).  2003. North Jetty Study, Grays Harbor, Washington.  Volume I:  Main Text.  ERDC-CHL-TR-03-12 
Acrobat PDF Document Available Here: Chapters 1 to 7 (Note:  Large File).

Acrobat PDF Document Available Here: Chapters 8 to 9 (Note:  Large File).

N.C. Kraus, and H.T. Arden, (eds.).  2003. North Jetty Study, Grays Harbor, Washington.  Volume II:  Appendices.  ERDC-CHL-TR-03-12 
Acrobat PDF Document Available Here: Appendix A-D (Note:  Large File).

Acrobat PDF Document Available Here: Appendix E-H (Note:  Large File).

Acrobat PDF Document Available Here: North Jetty Grays Harbor - Performance and Entrance Channel Maintenance (Display Poster for Grays Harbor Science Fair)
(Document reduced to print on 11"x17" size paper)

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